Such rollers are used in general to maintain a constant tension on the belt or chain within a determined range or to locally modify the routing of the belt or chain. The terms tensioner rollers and winding rollers, respectively, are thus used. In winding rollers, the pulley is mounted rotationally on a bolt or axle through the intermediary of a bearing, the roller then being attached directly or indirectly to the engine block or to a component of a tensioner roller device, for example an articulated or eccentric member. The bearing is any mechanical device enabling the creation of a pivot connection between the pulley and the bolt or axle, and to this end may be a rolling bearing or a plain bearing.
In general, a spacer is used in conjunction with the bolt or axle to attach the roller to its support. During this installation, it is desirable for the axle or bolt to be axially attached to the other components constituting the roller and comprising the pulley. This provides an assembly which cannot be dismantled, is easy to handle and transport and which may be installed easily.
To this end, a pulley device for a tensioner roller comprising a pulley, a bearing, a spacer supporting the bearing and a securing bolt that is axially immobilized in relation to the spacer is known from document FR 2 954 437. The relative axial retention of the securing bolt and of the spacer is achieved by means of a retaining ring designed to engage with a groove made in the securing bolt.
One of the disadvantages of this solution is that it requires a specific design for the securing bolt. Furthermore, a relatively large clearance must be left free on the frontal surface of the spacer to allow the installation of the retaining ring. This considerably reduces the area for contact between the spacer and its support.